Some brain-damaged patients could not stop imitating a stranger's strange gestures

Roughly forty-five percent of what you do in a day, according to a Duke University study Stephen Guise cites, isn't decided at all. It's habit. To understand why habits have that much power over you, it helps to think of the brain, in deliberately oversimplified terms, as two very different players.

One is the prefrontal cortex, sitting behind your forehead. It handles long-term thinking, weighs consequences, and wants things like fitness, a finished book, fluent French. Psychologist David Nowell describes everything else in the brain as dealing with what is, while the prefrontal cortex alone deals with what could be. The catch is that it tires quickly; it's an energy-hungry system, and when it's tired, or stressed, or has just made a difficult decision, it hands control to the other player.

That other player is the basal ganglia, a cluster of structures that recognizes and repeats patterns without needing to think about them. French neurologist Francois Lhermitte studied what happens when the prefrontal cortex is damaged and can no longer override this pattern-repeater. In his experiments, an examiner sat across from participants and performed odd, meaningless gestures: saluting, folding paper into an envelope, chewing paper, singing. People with healthy frontal lobes found this strange and did not copy him. But patients with damaged frontal lobes imitated him precisely, gesture for gesture, even when told beforehand not to, and even when the behavior was as extreme as urinating on a wall in front of others. Without a working prefrontal cortex, there was nothing left to override the brain's pull toward repeating what it sees.

This tells you something important about your own, undamaged brain: the pattern-repeating basal ganglia is always there, always strong, and your prefrontal cortex is the only thing holding it back from running the show entirely. Wendy Wood's research adds a second piece. Stress, she found, pushes people toward whatever they usually do, for better or worse, because a stressed or overwhelmed mind can't easily make fresh decisions and defaults to habit instead.

Put together, this explains why willpower alone, used forcefully and occasionally, rarely beats an established habit, good or bad. The prefrontal cortex gets outlasted every time it tries to fight the basal ganglia head-on with brute effort. The way to win, according to Guise, isn't strength. It's designing changes so small that the basal ganglia never mounts a real defense in the first place.

Stop trying to overpower your habits through sheer willpower, since your pattern-repeating basal ganglia will outlast your tired prefrontal cortex almost every time. Instead, notice when you're stressed, exhausted, or have just made a hard decision, because those are exactly the moments your brain defaults hardest to existing routines. On those moments, don't demand a big change from yourself; ask for something so small it doesn't register as a threat to the pattern-repeater. Give your prefrontal cortex easy wins it can actually deliver, rather than battles it's too depleted to fight. Over time, repeating those small wins is what quietly shifts the pattern your basal ganglia defaults to.